Vehicle seat reclining device

ABSTRACT

In this vehicle seat reclining device, the annular protrusion of a ratchet has a first region, a second region, and a third region, which are arranged circumferentially, and the outer side surface of the ratchet has a fourth region. The protrusion is shaped so that the third region extends further radially outward than the second region. As a result, the portion of the fourth region, which corresponds to the third region, extends further radially outward than the portion of the fourth region, which corresponds to the second region.

TECHNICAL FIELD

The present invention relates to a vehicle seat reclining device. Morespecifically, the present invention relates to a vehicle seat recliningdevice for adjusting a tilt angle of a seat back.

BACKGROUND ART

As a vehicle seat reclining device of related art, there is known adevice including a stepped lock mechanism capable of adjusting abackrest angle of a seat back at a constant pitch angle (PatentLiterature 1). The vehicle seat reclining device described above isconfigured as a joint device that connects the seat back to a seatcushion in a state where the backrest angle can be adjusted.Specifically, the vehicle seat reclining device described above includesa ratchet and a guide which are made of substantially disc-shaped metalmembers and which are assembled so as to be rotatable relative to eachother, and a lock mechanism that locks the relative rotation thereof.

The ratchet described above is coupled to a side frame by fitting andwelding a plurality of projections (so-called dowels) formed to protrudefrom an outer side surface portion of the ratchet into fitting holesformed in the side frame of the seat back.

CITATION LIST Patent Literature

-   Patent Literature 1: WO 2016/129423

SUMMARY OF INVENTION Technical Problem

In the related art, a part of an outer peripheral edge shape of theouter side surface portion of the ratchet is recessed inward in a radialdirection by half blanking for the purpose of forming a shape on aninner side surface portion side. Also, positions where some of theprojections (dowels) are formed and a welding space to the side frameare packed inward in the radial direction, which is disadvantageous interms of strength. One of the objects of the present invention is toexpand a coupling region of a ratchet to a seat frame outward in aradial direction in a vehicle seat reclining device.

Solution to Problem

[1] According to a first aspect of the present invention, a vehicle seatreclining device includes:

a disc-shaped ratchet and a disc-shaped guide, the ratchet and the guidebeing coaxially assembled in a relatively rotatable manner;

a lock mechanism provided between the ratchet and the guide, and capableof restricting relative rotation between the ratchet and the guide; and

a retaining ring retaining an assembled state of the ratchet and theguide, and

the lock mechanism includes: a plurality of poles supported by the guidemovably in a radial direction, the plurality of poles meshing with theratchet when moving outward in the radial direction so as to restrictthe relative rotation between the ratchet and the guide; and a cam formoving the plurality of poles outward or inward in the radial direction,

the ratchet has: an annular protruding portion where an outer peripheralportion of the ratchet protrudes to one side in an axial direction; andan outer side surface portion configured to face a seat frame on theother side in the axial direction of the ratchet,

the protruding portion has: a first region in which a specific pole ofthe plurality of poles is allowed to move outward in the radialdirection and to mesh with the ratchet; a second region in which thespecific pole is prevented from moving outward in the radial directionand from meshing with the ratchet; and a third region in which anotherpole is located when the specific pole is in the second region, thefirst region, the second region, the third region being arranged in aperipheral direction,

the outer side surface portion has a fourth region configured to be incontact and coupled with the seat frame, and

the protruding portion has a shape in which the third region extendsfurther outward in the radial direction than the second region, so thatthe fourth region has a shape in which a portion of the fourth region,which corresponds to the third region is wider outward in the radialdirection than a portion of the fourth region, which corresponds to thesecond region.

According to the first aspect, in the fourth region (coupling regiondescribed later) coupled with the seat frame of the outer side surfaceportion of the ratchet, the portion corresponding to the third region(other region described later) of the protruding portion has a shape iswider outward in the radial direction (shape of an expansion surfaceportion described later) than the portion corresponding to the secondregion (free region described later). Therefore, a seat reclining devicehaving such a configuration can expand the portion where the ratchet iscoupled to the seat frame to the outer side in the radial direction ascompared with a seat reclining device in related art.

[2] According to a second aspect of the present invention, in the firstaspect described above,

the outer side surface portion has a projection protruding toward theother side in the axial direction so as to be fitted into the seatframe, the projection being provided on the fourth region, and

the projection has a shape in which a length of the projection in theperipheral direction is equal to or less than a length of the thirdregion in the peripheral direction.

According to the second aspect, a wide space in which a space aroundboth ends of the projection (dowel) in the peripheral direction and aspace on the outer side in the radial direction of the projection(dowel) are continuous can be assigned in the fourth region (couplingregion). Therefore, it is possible to assign a wider area where theratchet is coupled to the seat frame.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view showing a schematic configuration of avehicle seat to which a vehicle seat reclining device according to afirst embodiment is applied.

FIG. 2 is an exploded perspective view of a main part of FIG. 1.

FIG. 3 is an exploded perspective view of FIG. 2 viewed from an oppositeside.

FIG. 4 is an exploded perspective view of the vehicle seat recliningdevice.

FIG. 5 is an exploded perspective view of FIG. 4 viewed from an oppositeside.

FIG. 6 is an outer side view of the vehicle seat reclining device.

FIG. 7 is an inner side view of the vehicle seat reclining device.

FIG. 8 is a front side view of the vehicle seat reclining device.

FIG. 9 is a sectional view taken along a line IX-IX of FIG. 1.

FIG. 10 is a sectional view taken along a line X-X of FIG. 8 showing alocked state of the vehicle seat reclining device.

FIG. 11 is a sectional view corresponding to FIG. 10 showing an unlockedstate of the vehicle seat reclining device.

FIG. 12 is a sectional view showing a state in which a ratchet is turnedto a free region from the state shown in FIG. 11.

FIG. 13 is a sectional view showing a state in which a locking operationof the vehicle seat reclining device from the state shown in FIG. 12 isblocked.

FIG. 14 is a sectional view showing a state in which the ratchet isturned to an end position of the free region from the state shown inFIG. 12.

FIG. 15 is an enlarged view of an XV part in FIG. 9.

FIG. 16 is a sectional view showing a state in which a rotating cam ispressed against a guide wall by being biased.

FIGS. 17(a) to 17(d) are sectional views showing the change of each polein the locking operation in accordance with the change in a rotationposition of the ratchet, divided into four cases.

FIGS. 18(a) to 18(d) are schematic diagrams showing a positionalrelationship between riding protrusions of each pole and a protrudingportion of the ratchet in FIGS. 17(a) to 17(d).

FIG. 19 is an outer side view of each pole.

FIG. 20 is an inner side view of each pole.

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment for carrying out the present invention aredescribed with reference to drawings.

First Embodiment

(Schematic Configuration of Seat Reclining Device 4)

First, the configuration of a vehicle seat reclining device 4(hereinafter, simply referred to as “device 4”) according to the firstembodiment will be described with reference to FIGS. 1 to 20. In thefollowing description, directions such as front, rear, upper, lower,left, and right refer to respective directions shown in the drawings.Further, a “seat width direction” refers to a left-right direction of aseat 1.

As shown in FIG. 1, the device 4 according to the present embodiment isapplied to the seat 1 that constitutes a right side seat of anautomobile. The device 4 described above is configured as a seatreclining adjustment mechanism that connects a seat back 2 that servesas a backrest portion of the seat 1 described above to a seat cushion 3that serves as a seating portion in a state in which an backrest anglecan be adjusted. Specifically, the device 4 described above is providedbetween the seat back 2 and the seat cushion 3 described above such thata pair of left and right devices 4 are provided. The device 4 isconfigured to fix or release the backrest angle of the seat back 2 bybeing switched integrally between a locked state and an unlocked state.

Specifically, the devices 4 described above are provided betweenrespective lower end portions of side frames 2F forming left and rightside frames of the seat back 2 described above and respective recliningplates 3F connected to rear end portions of left and right side framesof the seat cushion 3 located on an outer side in the seat widthdirection, so that the devices 4 can be relatively rotated or stoppedrelative to each other coaxially (see FIGS. 2 and 3).

The devices 4 described above are usually held in a locked state inwhich the backrest angle of the seat back 2 is fixed. The devices 4 arereleased from the locked state all at once by an operation of pulling upa reclining lever 5 provided on a right side portion of the seat cushion3 which is on a vehicle outer side so as to be switched to an unlockedstate in which the backrest angle of the seat back 2 can be changed. Thedevices 4 are returned to the locked state again by being biased afterthe operation of pulling up the reclining lever 5 described above isreturned.

Here, return springs 6 that always apply a spring biasing force to theseat back 2 in a direction in which the seat back 2 rotates to tiltforward are hooked between the side frames 2F on the left and rightsides of the seat back 2 and the reclining plates 3F arranged on theouter side thereof. Due to the rotational biasing force of these returnsprings 6, the seat back 2 is lifted up to a position where the seatback 2 comes into contact with the back of a seated occupant byreleasing the fixed state of the backrest angle by the device 4described above, such that the backrest angle can be freely adjustedback and forth in accordance with the movement of tilting back and forthby the back of the seated occupant. According to such a configuration,the seat back 2 is configured such that the backrest angle can be easilyadjusted.

The seat back 2 can rotate in a seat front-rear direction in a rotationregion of about 180 degrees with respect to the seat cushion 3 describedabove between a forward tilting position where the seat back 2 is foldedup to an upper surface of the seat cushion 3 and a backward tiltingposition where the seat back 2 is tilted substantially straight to therear side. Among the rotation region described above, a rotation regionof about 90 degrees from an upright position where the backrest angle ofthe seat back 2 is substantially straight to the upper side to thebackward tilting position described above is set as a “lock region” inwhich the backrest angle of the seat back 2 is returned to a fixed statewhen the operation of pulling up the reclining lever 5 is released.Further, a rotation region for the backrest angle of the seat back 2from the upright position to the forward tilting position describedabove is set as a “free region” in which the backrest angle of the seatback 2 is maintained in a released state without being returned to thefixed state even though the operation of pulling up the reclining lever5 is released.

The lock region and the free region described above respectivelycorrespond to a lock region A1 and a free region A2 set in the device 4described later. With the setting of the free region A2 described above,when the reclining lever 5 is operated while a person is not seated onthe seat 1, once the seat back 2 is tilted to a position that enters thefree region A2 due to the biasing of the return spring 6 describedabove, the seat back 2 is tilted to a forward leaning positionthereafter even if the operate on the reclining lever 5 is notcontinued. Here, the lock region A1 corresponds to a “first region” ofthe present invention, and the free region A2 corresponds to a “secondregion” of the present invention.

As shown in FIGS. 2 and 3, specifically, the device 4 described aboveincludes a ratchet 10 that is integrally coupled to an outer surface ofthe side frame 2F on each side of the seat back 2 described above, and aguide 20 that is integrally coupled to an inner surface of the recliningplate 3F on each side. The device 4 is configured such that the backrestangle of the seat back 2 is fixed or released by locking or unlockingthe relative rotation between the ratchet 10 and the guide 20. Here, theside frame 2F described above corresponds to a “seat frame” of thepresent invention.

(Specific Configuration of Device 4)

Hereinafter, a specific configuration of the pair of left and rightdevices 4 described above will be described in detail. Since the devices4 have the same configuration and are symmetrical with respect to eachother, the configuration of one device arranged on the vehicle outerside (right side) shown in FIGS. 2 to 3 will be described as arepresentative in the following description.

As shown in FIGS. 4 and 5, the device 4 includes the substantiallydisc-shaped ratchet 10 and guide 20 that are assembled with each otherin an axial direction, three poles 30 assembled between the ratchet 10and guide 20, a rotating cam 40 configured to move these three poles 30inward and outward in the radial direction, a lock spring 50 formed of aspiral spring that biases the rotating cam 40 against the guide 20 in adirection of a lock rotation movement, and a substantially cylindricalouter peripheral ring 60 that is mounted across outer peripheralportions of the ratchet 10 and the guide 20 so as to hold the ratchet 10and the guide 20 in an assembled state in the axial direction. Theratchet 10, the guide 20, the three poles 30, and the rotating cam 40are configured to be hardened by being subjected to a quenchingtreatment after the press molding such that a structural strength isenhanced. Here, the rotating cam 40 described above corresponds to a“cam” of the present invention. Hereinafter, a specific configuration ofeach member constituting the device 4 described above will besequentially described in detail.

(Ratchet 10)

As shown in FIG. 4, the ratchet 10 is formed by one metal plate memberbeing cut into a substantially disc shape and subjected to half blankingin places in a plate thickness direction (the axial direction).

Specifically, an outer peripheral edge portion of a disc main body 11 ofthe ratchet 10 described above is formed with a cylindrical portion 12that protrudes in a substantially cylindrical shape in the axialdirection, which is a direction of attachment to the guide 20.Specifically, the cylindrical portion 12 described above is formed byhalf blanking so that the outer peripheral edge portion of the disc mainbody 11 protrudes in two steps in the axial direction, and is formed ina stepped cylindrical shape having an inner and outer two-stepcylindrical shape in which an intermediate cylindrical portion 13smaller in the axial direction than the cylindrical portion 12 andprotruding in a substantially cylindrical shape is formed on an innerperipheral side. Here, the intermediate cylindrical portion 13 describedabove corresponds to a “protruding portion” of the present invention.

An inner peripheral surface of the cylindrical portion 12 describedabove is formed with inner peripheral teeth 12A whose tooth surfacesface inward in the radial direction such that the inner peripheral teeth12A are continuously arranged over an entire area in a peripheraldirection. The inner peripheral teeth 12A described above are formed ina tooth surface shape with which outer peripheral teeth 31 formed on anouter peripheral surface of each pole 30 described later can be meshedby being pressed from an inner side in the radial direction.Specifically, the inner peripheral teeth 12A described above areconfigured such that the tooth surfaces are arranged in the peripheraldirection at equal intervals with a pitch of 2 degrees from each other.

Further, an inner peripheral surface of the intermediate cylindricalportion 13 is formed with three peripheral directions (region 13A,region 13B, and region 13C) in which an inner diameter from the centralportion (central axis C) and a length in the peripheral direction areindividually set, a first projection 13D and a second projection 13Ethat protrude inward in the radial direction from a boundary of some ofthese regions, and an escape recess 13F that is recessed outward in theradial direction at a boundary position of the region 13C with thesecond projection 13E described above.

The region 13A, the region 13B, and the region 13C are each formed in aninner peripheral surface shape that is curved so as to draw an arc of aconcentric circle around the central portion (central axis C).Specifically, the regions 13A and 13C are formed in an inner peripheralsurface shape having a larger inner diameter than the region 13B, andthe regions 13A and 13C are formed in an inner peripheral surface shapehaving the same inner diameter.

As shown in FIGS. 10, 17(a) and 18(a), when a main pole P1 of the threepoles 30 to be described later is arranged to overlap the region 13A inthe peripheral direction by rotation of the ratchet 10, the region 13Adescribed above constitutes the lock region A1 of the main pole P1 thatallows the main pole P1 to move outward in the radial direction so as tomesh with the inner peripheral teeth 12A of the ratchet 10 and to belocked. Here, the main pole P1 described above corresponds to a“specific pole” of the present invention.

Further, when the main pole P1 is arranged to overlap the region 13Adescribed above in the peripheral direction, the region 13B and theregion 13C described above function as other regions A3 arranged tooverlap the remaining two sub poles P2 of the three poles 30 in theperipheral direction, such that the sub poles P2 are allowed to move soas to mesh with the inner peripheral teeth 12A of the ratchet 10. Here,the other regions A3 correspond to a “third region” of the presentinvention.

However, when the main pole P1 described above is arranged to overlapthe region 13B in the peripheral direction by rotation of the ratchet 10as shown in FIG. 12, the region 13B function as the free region A2 ofthe main pole P1, such that the main pole P1 is prevented from movingoutward in the radial direction to mesh with the inner peripheral teeth12A of the ratchet 10 on the way as shown in FIGS. 13, 17(b), and 18(b).Here, each sub pole P2 described above corresponds to “another pole” ofthe present invention.

When the main pole P1 is arranged to overlap the region 13B describedabove in the peripheral direction, the region 13C and the region 13Adescribed above function as the other regions A3 arranged to overlap theremaining two sub poles P2 in the peripheral direction, such thatmovement of each sub pole P2 synchronized with the movement of the mainpole P1 described above escapes in these regions.

That is, in the intermediate cylindrical portion 13 of the ratchet 10described above, the region 13A described above constitutes the lockregion A1 in which the lock operation of the main pole P1 is allowed(see FIGS. 10, 17(a) and 18(a)), and the region 13B constitutes the freeregion A2 in which the lock operation of the main pole P1 is blocked byriding and the ratchet 10 can be freely rotated in the peripheraldirection while being held in the unlocked state (see FIGS. 13, 17(b)and 18(b)).

As shown in FIGS. 10, 17(a) and 18(a), when the main pole P1 is arrangedto overlap the region 13A in the peripheral direction as describedabove, the region 13B and the region 13C function as the other regionsA3 separately, so that the remaining two sub poles P2 are allowed toperform the lock operation in synchronization with the movement of themain pole P1. Further, as shown in FIGS. 13, 17(b) and 18(b), when themain pole P1 described above is arranged to overlap the region 13B inthe peripheral direction by the rotation of the ratchet 10 describedabove, the region 13C and the region 13A function as the other regionsA3 separately, so that the lock operation of the remaining two sub polesP2 performed in synchronization with the movement of the main pole P1 isblocked midway.

As described above, the intermediate cylindrical portion 13 of theratchet 10 controls to allow and block the lock operation of the mainpole P1 by the region 13A and the region 13B described above, and isconfigured such that the movement of the remaining two sub poles P2 insynchronization with the movement of the main pole P1 can escape byother regions (other regions A3) where the remaining two sub poles P2are located at this time.

In a case where the main pole P described above is pushed outward in theradial direction at a halfway point and is accidentally pressed againsta step between the region 13A and the region 13B in the peripheraldirection when being moved from the lock region A1 (region 13A) to thefree region A2 (region 13B) by the rotation of the ratchet 10 (i.e. in acase where the arrangement is shown in FIGS. 17(b) and 18 (b)), thefirst projection 13D and the second projection 13E function to come intocontact with these two sub poles P2 at the same time as shown in FIGS.17(c) and 18 (c) so as to distribute a load caused thereby to the othertwo sub poles P2 instead of concentrate only on the main pole P1.

That is, when the main pole P described above is pressed against thestep between the region 13A and the region 13B in the peripheraldirection due to the rotation of the ratchet 10, the first projection13D and the second projection 13E described above are formed atpositions where the first projection 13D and the second projection 13Eare pressed against the remaining two sub poles P2 in the peripheraldirection.

As shown in FIGS. 14, 17(d), and 18(d), when the main pole P1 describedabove moves to an end position in the peripheral direction on the region13B which is the free region A2 due to the rotation of the ratchet 10,the escape recess 13F is configured to be disengaged from the ridingstate so that the main pole P can be meshed with the inner peripheralteeth 12A of the ratchet 10 at that position. By the escape recess 13F,the ratchet 10 is tilted down to an end position of the free region A2,that is, the forward tilting position where the seat back 2 is folded upon the upper surface of the seat cushion 3 described above withreference to FIG. 1, so that the device 4 is locked at that position andthe seat back 2 can be switched to a state where the rotation isstopped. As a result, the seat back 2 can be locked in the forwardtilting position so as not to loosely move.

As shown in FIGS. 4 and 5, a through hole 11A penetrating in around holeshape is formed at a central portion (on the central axis C) of the discmain body 11 of the ratchet 10 described above. An operation pin 5A,which is inserted and mounted in a central portion (on the central axisC) of the rotating cam 40 described later, is inserted through thethrough hole 11A in a rotation-free state from an outer side in theaxial direction. Further, as shown in FIG. 5, on an outer surface of thedisc main body 11 of the ratchet 10 described above, projections(hereinafter, referred to as “dowels 14”) that protrude by being pushedout in an arcuate shape in the axial direction are formed at threepositions in the peripheral direction, which are positions arranged onthe same circumference around the central portion (on the central axisC) of the disc main body 11.

The dowels 14 described above are formed in such a manner that one dowelis housed in each forming region in the peripheral direction in whichthe region 13A, the region 13B, and the region 13C of the intermediatecylindrical portion 13 described above are formed. As shown in FIG. 3,the ratchet 10 having the configuration described above is assembled insuch a manner that the outer surface of the disc main body 11 thereof isin surface contact with the outer surface of the side frame 2F of theseat back 2 described above, and a contact portion therebetween inwelded so that the ratchet 10 is integrally coupled to the side frame 2Fof the seat back 2 (welding portion W).

Specifically, the ratchet 10 described above is assembled in a statewhere three dowels 14 formed on the outer surface of the disc main body11 are respectively fitted in three fitting holes 2Fa correspondinglyformed in the side frame 2F of the seat back 2 and penetrating in asubstantially arc shape, and peripheral regions (coupling regions A4) ofthese fitted parts are joined and coupled by laser welding in a state ofsurface contact with the side frame 2F (welding portion W).

More specifically, the outer surface of the disc main body 11 of theratchet 10 described above is formed with the coupling regions A4 whichare abutted against the side frames 2F in a surface contact state andlaser-welded on the outer side in the radial direction and on both sidesin the peripheral direction of the regions where these three dowels 14are formed. As shown in FIG. 7, the coupling regions A4 described aboveare configured such that the region 13A and the region 13C of theintermediate cylindrical portion 13 which are formed on the outerperipheral edges of respective coupling regions A4 are located atpositions on the outer side in the radial direction than the region 13B.Therefore, the coupling regions A4 are configured such that regions inthe forming regions in the peripheral direction in which the region 13Aand the region 13C are formed each have an expansion surface portion 11Bwhose area is expanded in the radial direction as compared with a regionin the forming region in the peripheral direction in which the region13B is formed. Here, the coupling region A4 corresponds to a “fourthregion” of the present invention.

According to such a configuration, the outer surface of the disc mainbody 11 of the ratchet 10 described above is configured such that thesetwo coupling regions A4 that each have the expansion surface portion 11Bin the respective forming regions in the peripheral direction in whichthe region 13A and the region 13C are formed are firmly welded to theside frames 2F more widely abutted toward the outer side in the radialdirection than the one coupling region A4 in the forming region in theperipheral direction in which the region 13B is formed.

More specifically, the welding of the outer surface of the disc mainbody 11 of the ratchet 10 described above to the side frames 2F isperformed in such a manner that each dowel 14 is surrounded from anouter region in the radial direction across both side regions in theperipheral direction in a C-shape so that welding beads are inserted(welding portion W). The side frame 2F described above is formed with apassage hole 2Fb that allows the operation pin 5A, which is passedthrough the through hole 11A formed at the central portion (on thecentral axis C) of the ratchet 10 described above, to pass throughtoward the outer side in the axial direction.

(Guide 20)

As shown in FIG. 5, the guide 20 is formed by one metal plate memberbeing cut into a substantially disc shape with an outer diameterslightly larger than that of the ratchet 10 and subjected to the halfblanking in places in the plate thickness direction (the axialdirection).

Specifically, on an outer peripheral edge portion of a disc main body 21of the guide 20 described above, a cylindrical portion 22 is formed toprotrude in a substantially cylindrical shape in the axial direction,which is a direction of attachment to the ratchet 10. The cylindricalportion 22 is formed such that an inner diameter thereof is slightlylarger than the outer diameter of the cylindrical portion 12 of theratchet 10 described above. As shown in FIG. 9, the guide 20 describedabove is set such that the cylindrical portion 12 of the ratchet 10described above is inserted into the cylindrical portion 22 of the guide20 in the axial direction.

Accordingly, the guide 20 and the ratchet 10 are assembled in a statewhere the respective cylindrical portions 22, 12 thereof are looselyfitted with each other inward and outward in the radial direction, suchthat relative rotation therebetween is enabled in a state of beingsupported inward and outward. Then, the guide 20 described above ismounted in a state where the outer peripheral ring 60 to be describedlater crosses from an outer peripheral side between the cylindricalportion 22 and the cylindrical portion 12 of the ratchet 10 describedabove, so that the guide 20 is assembled while being prevented fromcoming off the ratchet 10 in the axial direction via the outerperipheral ring 60 (see FIGS. 2 and 3, and FIGS. 6 to 9).

As shown in FIG. 5, guide walls 23 which are formed by being pushed outin a half-blanking shape so as to protrude in a substantially fan shapein the axial direction, which is a direction of assembling to theratchet 10, are formed at three positions in the peripheral direction onan inner surface of the disc main body 21 of the guide 20 describedabove. These guide walls 23 are formed such that respective outerperipheral surfaces thereof in the radial direction are curved so as todraw arcs of a concentric circular drawn around a central portion(central axis C) thereof. Each of the guide walls 23 described above isset so as to be loosely fitted into the cylindrical portion 12 of theratchet 10 which is assembled in the cylindrical portion 22 of the guide20 described above.

By forming the guide walls 23 described above, pole accommodatinggrooves 24A are formed in regions among arrangement of the guide walls23 in the peripheral direction on the inner surface of the disc mainbody 21 described above, so that each of the three poles 30 describedlater can be set to be slidable inward and outward in the radialdirection. Further, a cam accommodating groove 24B is formed in a centerregion on the inner surface of the disc main body 21 surrounded by theguide walls 23 described above, so that the rotating cam 40 describedlater can be set to be rotated axially.

As shown in FIGS. 10 and 11, the guide walls 23 described above areapplied to the respective poles 30 set correspondingly in the poleaccommodating grooves 24A described above so as to face each other fromboth sides in the peripheral direction by restriction surfaces 23A,which are both side surfaces in the peripheral direction facing eachpole accommodating groove 24A, and are configured to support each pole30 from both sides in the peripheral direction so as to guide each pole30 to be slidable only inward and outward in the radial direction.

Further, the guide walls 23 described above are applied to the rotatingcam 40 set in the cam accommodating groove 24B described above so as toface each other from the outer side in the radial direction by a supportsurface 23B, which is an inner peripheral surface in the radialdirection facing the cam accommodating groove 24B, and are configured tosupport the rotating cam 40 from the outer side in the radial directionso as to guide the rotating cam 40 at the central portion (on thecentral axis C) on the disc main body 21 of the guide 20 to be rotatableonly in the peripheral direction.

As described in FIG. 5, a play filling pin 21C that is inserted into awedge-shaped play filling hole 35 formed in the main pole P1 so as toprotrude in a columnar shape in the axial direction is formed on aforming region of the pole accommodating groove 24A in which the mainpole P1 is set on the inner surface of the disc main body 21 of theguide 20 described above. As shown in FIG. 11, when the main pole P1described above is pulled inward in the radial direction and is notmeshed with the inner peripheral teeth 12A of the ratchet 10, the playfilling pin 21C described above is located in an outer region of thewedge-shaped play filling hole 35 in the radial direction where a holewidth is wide and does not block the movement of the main pole P1.

However, as shown in FIG. 10, as the main pole P1 is pushed outward inthe radial direction and meshed with the inner peripheral teeth 12A ofthe ratchet 10, the play filling pin 21C described above is pressed intoan inner region in the radial direction where the hole width is narrowin the wedge-shaped play filling hole 35 of the main pole P1, so thatthe play filling pin 21C can be switched to a state in which the play ofthe main pole P1 in the peripheral direction is prevented. According tosuch a configuration, the main pole P1 is meshed with the innerperipheral teeth 12A of the ratchet 10 in a state where the play in theperipheral direction is prevented, and the ratchet 10 and the guide 20are locked via the main pole P1 in a state where the play in theperipheral direction therebetween is prevented.

As shown in FIGS. 4 and 5, each of the guide walls 23 described above isformed with a floating island-shaped bead portion 23C that is pushed outin a half-blanking shape toward a side opposite to the axial directionwhich is the direction of assembling to the ratchet 10 at anintermediate portion where a peripheral edge of a protruding regionwhose shape is expanded in the peripheral direction and the radialdirection is left. Each bead portion 23C is formed as described above,so that each guide wall 23 is configured to have high structuralstrength capable of firmly supporting each pole 30 from both sides inthe peripheral direction without reducing a contact area with each pole30 for supporting each pole 30 from both sides in the peripheraldirection by the restriction surfaces 23A.

Further, at the central portion (on the central axis C) of the disc mainbody 21 of the guide 20 described above, a through hole 21A penetratingin a substantially round hole shape is formed in which the lock spring50 to be described later is accommodated. The through hole 21A describedabove is formed with a hanging hole 21Aa which extends a slender holeshape from a part of a hole shape of the through hole 21A toward theouter side in the radial direction. An outer end portion 52 of the lockspring 50 set in the through hole 21A described above is fitted into thehanging hole 21Aa in the axial direction so as to be integrally fixed inthe peripheral direction.

As shown in FIG. 4, dowels 21B protruding in a substantially cylindricalshape in the axial direction are formed on an outer surface of the discmain body 21 of the guide 20 described above at three positions in theperipheral direction. Each of these dowels 21B is formed in such amanner that it is pushed out in the axial direction one by one inregions corresponding to back sides of respective pole accommodatinggrooves 24A described above on the outer surface of the disc main body21 described above.

As shown in FIG. 2, the guide 20 having the configuration describedabove is in a state of being firmly and integrally coupled to thereclining plate 3F by the dowels 21B protruding from the outer surfaceof the disc main body 21 described above being fitted into and weldedwith the corresponding fitting holes 3Fa formed in the reclining plate3F. The reclining plate 3F described above is formed with a passage hole3Fb that allows the operation pin 5A, which is passed through thethrough hole 21A formed at the central portion (on the central axis C)of the guide 20 described above, to pass through toward the outer sidein the axial direction.

(Pole 30)

As shown in FIGS. 4 and 5, these three poles 30 are separately formed byone metal plate member being cut into a substantially rectangular shapeand subjected to the half blanking in places in the plate thicknessdirection (the axial direction). Specifically, each pole 30 describedabove has a shape in which an offset surface portion 30B forming aregion on an inner peripheral side in the radial direction of the polesis pushed out in a half-blanking shape by an amount corresponding to asubstantially plate thickness in the axial direction, which is thedirection of assembling to the ratchet 10, with respect to a main bodysurface portion 30A forming a region on an outer peripheral side.

Further, a specific one pole of the three poles 30 described above isconfigured as the main pole P1 that has a partly different shape fromthe other two sub poles P2 so as to be functionally distinguished. Thespecific difference will be described later.

As shown in FIGS. 10 and 11, each pole 30 described above is set so asto be accommodated one by one in respective pole accommodating grooves24A formed on the inner surface of the disc main body 21 of the guide 20described above. With such a setting, each pole 30 is provided in astate of being supported in a planar shape from both sides in theperipheral direction by the restriction surfaces 23A of the guide walls23 facing the respective pole accommodating grooves 24A from both sidesin the peripheral direction, and is supported so as to be movable onlyinward and outward in the radial direction along the restrictionsurfaces 23A.

Specifically, as shown in FIG. 9, when each pole 30 described above isset in the respective pole accommodating grooves 24A described above,the main body surface portions 30A of the poles 30 are set so as to beabutted against the inner surface of the disc main body 21 of the guide20. Therefore, each of the poles 30 is set such that the innerperipheral teeth 12A of the cylindrical portion 12 of the ratchet 10assembled in the cylindrical portion 22 of the guide 20 described aboveface each other in the radial direction at a position on the outer sidein the radial direction of the main body surface portion 30A.

Further, the offset surface portion 30B of each pole 30 described aboveis set so as to be spaced from the inner surface of the disc main body21 of the guide 20 described above in the axial direction, and tooverlap the intermediate cylindrical portion 13 of the ratchet 10described above in the axial direction.

As shown in FIG. 4, on an outer peripheral surface in the radialdirection of the main body surface portions 30A of each pole 30described above, the outer peripheral teeth 31 whose tooth surfaces faceoutward in the radial direction are formed in a shape that iscontinuously arranged over an entire area in the peripheral direction.The outer peripheral surface in the radial direction on which the outerperipheral teeth 31 of each pole 30 described above are formed is formedinto a curved surface shape along the inner peripheral surface of thecylindrical portion 12 on which the inner peripheral teeth 12A of theratchet 10 described above are formed.

According to such a configuration, the outer peripheral teeth 31 of eachpole 30 are pressed against the inner peripheral teeth 12A of theratchet 10 from the inner side in the radial direction, so that theentire teeth are meshed with the inner peripheral teeth 12A of theratchet 10. Specifically, the outer peripheral teeth 31 of each pole 30are configured such that the tooth surfaces are arranged in theperipheral direction at equal intervals with a pitch of 2 degrees fromeach other, as the inner peripheral teeth 12A.

However, more strictly, with reference to FIG. 10, the outer peripheralteeth 31 of each pole 30 described above are formed in such manner thattooth surfaces at the center in the peripheral direction enter and meshdeepest with the inner peripheral teeth 12A of the ratchet 10, and atooth height becomes smaller as the entering depth with respect to theinner peripheral teeth 12A of the ratchet 10 gradually decreases towardboth end sides in the peripheral direction.

According to such a configuration, in each pole 30, in addition to thetooth surfaces at the center position where the tooth surfaces areoriented straight in an entering direction thereof, other tooth surfaceswhere direction of the tooth surfaces is tilted in a direction differentfrom the entering direction from the same center position toward bothend sides in the peripheral direction can also be appropriately meshedwith the tooth surfaces of the corresponding inner peripheral teeth 12Aof the ratchet 10 by the movement of each pole 30 toward the outer sidein the radial direction without being replaced. The specific toothsurface shape of the outer peripheral teeth 31 is the same as thatdisclosed in the literature such as JP-A-2015-29635, and therefore adetailed description thereof will be omitted.

According to such a configuration, when the outer peripheral teeth 31are meshed with the inner peripheral teeth 12A of the ratchet 10, eachpole 30 may receive an action of a biased force such that the entirebody is pushed and tilted in either one of the peripheral directions byan action of a pressing force from the inner side in the radialdirection, with the deepest meshed center position in the peripheraldirection as a fulcrum. However, the above action is appropriatelysuppressed by the action of the play filling pin 21C provided on theguide 20 being pressed into the wedge-shaped play filling hole 35 withthe play being filled in the peripheral direction when the main pole P1is to be meshed with the ratchet 10.

As shown in FIG. 9, each pole 30 described above is set in such a mannerthat the rotating cam 40 which is described later and set at the centralportion (on the central axis C) of the guide 20 faces the radialdirection in a region at the inner side of the radial directionsurrounded by the main body surface portions 30A. With such a setting,each pole 30 is configured such that the main body surface portions 30Aare provided side by side at positions on the outer side in the radialdirection of the rotating cam 40, and the offset surface portions 30Bare provided so as to overlap the rotating cam 40 in the axialdirection.

Here, as shown in FIG. 5, the inner peripheral surface of the main bodysurface portion 30A of each pole 30 described above is formed withpressed surface portions 32 which face the rotating cam 40 describedabove in the radial direction and which receive an acting force pressedfrom the inner side to the outer side in the radial direction as therotating cam 40 rotates. Further, a pull-in hole 33 is formed at anintermediate portion of the offset surface portion 30B of each pole 30described above and penetrates in the axial direction so as to beoperated such that a corresponding pull-in pin 42 formed on the rotatingcam 40 described above is inserted therein and pulled inward in theradial direction as the rotating cam 40 rotates. Further, at anintermediate portion of the main body surface portion 30A of each pole30 described above, a riding protrusion 34 that is pushed out in ahalf-blanking shape in the same axial direction as the offset surfaceportion 30B is formed.

As shown in FIG. 10, the rotating cam 40 described above is rotated in acounterclockwise direction in the figure by a spring biasing force ofthe lock spring 50 described later which is hooked between the rotatingcam 40 and the guide 20, so that the pressed surface portions 32 of eachpole 30 described above is pressed from the inner side to the outer sidein the radial direction by a corresponding pressing portion 44 formed onan outer peripheral surface portion of the rotating cam 40. By the abovepressing, the outer peripheral teeth 31 of each pole 30 are pressedagainst the inner peripheral teeth 12A of the ratchet 10 described aboveto be meshed with each other, and are held in such a meshed state. As aresult, the poles 30 are integrally coupled to the ratchet 10 in theperipheral direction, and the relative rotation between the ratchet 10and the guide 20 is locked via each pole 30.

Further, as shown in FIG. 11, the rotating cam 40 described above isrotated in a clockwise direction shown in the figure against the springbiasing force of the lock spring 50 by the operation of the reclininglever 5 described above, so that the pull-in hole 33 of each pole 30described above is pulled inward in the radial direction by thecorresponding pull-in pin 42 of the rotating cam 40 inserted therein. Bythe above pulling, the outer peripheral teeth 31 of each pole 30 do notmesh with the inner peripheral teeth 12A of the ratchet 10 describedabove, and are held in such a state (unlocked state). As a result, therotation locked state between the ratchet 10 and the guide 20 describedabove is released.

As shown in FIG. 9, the riding protrusion 34 of each pole 30 describedabove is pushed out in a half-blanking shape in the same axial directionas the offset surface portion 30B of each pole 30 described above to thesame position, and an outer peripheral surface portion 34A thereof isprovided so as to face the inner peripheral surface of the intermediatecylindrical portion 13 of the ratchet 10 described above in the radialdirection. As shown in FIGS. 10, 17(a), and 18(a), when a rotationposition of the ratchet 10 described above with respect to the guide 20is in the state of the lock region A1 described above, even if each pole30 described above is pushed outward in the radial direction by therotating cam 40, the riding protrusion 34 of each pole 30 describedabove is not pressed against the inner peripheral surface of theintermediate cylindrical portion 13 of the ratchet 10 so that themovement of each pole 30 meshing with the inner peripheral teeth 12A ofthe ratchet 10 is not blocked.

However, as shown in FIGS. 13, 17(b), and 18(b), by changing therotation position of the ratchet 10 described above with respect to theguide 20 to the state of the free region A2 described above, when eachpole 30 described above is pushed outward in the radial direction by therotating cam 40, the riding protrusion 34 of each pole 30 describedabove is pressed against the inner peripheral surface of theintermediate cylindrical portion 13 of the ratchet 10 to ride up, sothat the movement of each pole 30 meshing with the inner peripheralteeth 12A of the ratchet 10 is stopped at an intermediate position.

Specifically, the riding protrusions 34 of each pole 30 described aboveare configured such that diameter dimensions from the central portion(on the central axis C) of the guide 20 to the outer peripheral surfaceportion 34A of the main pole P1 and the other two sub poles P2 aredifferent from each other, that is, forming positions in the radialdirection are different from each other. Specifically, the ridingprotrusion 34 of the main pole P1 is formed at a position which isprojected more outward in the radial direction than the ridingprotrusions 34 of the other two sub poles P2.

As shown in FIGS. 10, 17(a) and 18(a), when the riding protrusion 34 ofthe main pole P1 described above is arranged to overlap the region 13A(lock region A1) of the intermediate cylindrical portion 13 of theratchet 10 in the peripheral direction, even if the riding protrusion 34is pushed outward in the radial direction by the rotating cam 40, theriding protrusion 34 is not pushed out to a position riding on theregion 13A, so that the movement of the main pole P1 meshing with theinner peripheral teeth 12A of the ratchet 10 is not blocked.

At this time, the riding protrusions 34 of the other two sub poles P2are formed at positions on the inner side of the radial direction thanthe riding protrusion 34 of the main pole P1 described above, so thateven if the riding protrusions 34 are arranged to respectively overlap,in the peripheral direction, the region 13B and the region 13C (otherregions A3) that protrude inward in the radial direction than the region13A described above, the riding protrusions 34 are also not pushed outto positions riding on the region 13B and region 13C at the time ofbeing pushed outward in the radial direction by the rotating cam 40, andtherefore, the movement of each sub pole P2 meshing with the innerperipheral teeth 12A of the ratchet 10 is not blocked.

Further, as shown in FIGS. 13, 17(b), and 18(b), when the ridingprotrusion 34 of the main pole P1 described above is arranged to overlapthe region 13B (free region A2) of the intermediate cylindrical portion13 of the ratchet 10 in the peripheral direction, the riding protrusion34 is pushed outward in the radial direction by the rotating cam 40 toride on the region 13B, so that the movement of the main pole P1 meshingwith the inner peripheral teeth 12A of the ratchet 10 is stopped at theintermediate position.

However, at this time, even if the riding protrusions 34 of the othertwo sub poles P2 are arranged to overlap the corresponding region 13Cand region 13A (other regions A3) respectively in the peripheraldirection, the riding protrusions 34 are also not pushed out to thepositions riding on the region 13C and region 13A at the time of beingpushed outward in the radial direction by the rotating cam 40, so thatthe movement of each sub pole P2 toward the outer side of the radialdirection is not stopped at an intermediate position.

Even with such a configuration, the movement of the sub poles P2 towardthe outer side of the radial direction of the main pole P1 is stopped atthe intermediate position so that the rotation of the rotating cam 40 isaccordingly stopped, and the sub poles P2 are not pushed outward furtherin the radial direction, so as to hold together with the main pole P1 inthe unlocked state in which they are prevented from being pressedagainst the inner peripheral teeth 12A of the ratchet 10. Each ridingprotrusion 34 formed on these two sub poles P2 described above has achamfered inclined surface 34B at a corner on one end side in theperipheral direction on the outer peripheral surface portion 34Athereof.

Each of the inclined surfaces 34B described above functions as an escapeportion that allows the riding protrusions 34 of the sub poles P2 topass over in the peripheral direction while escaping to the outer sidein the radial direction by an inclined guide so as not to abut againstthe first projection 13D and the second projection 13E in the peripheraldirection, when the ratchet 10 is rotated in a direction in which theratchet 10 is returned from the free region A2 to the lock region A1without operating the reclining lever 5 (when the seat back 2 is liftedup to the rear side), from a state where the riding protrusion 34 of themain pole P1 described above rides on the free region A2 (region 13B) ofthe ratchet 10, and the riding protrusions 34 of the sub poles P2 arelocated on the region 13C and the region 13A respectively as shown inFIGS. 13, 17(b), and 18(b).

Further, as shown in FIGS. 4 and 5, in the main body surface portion 30Aof the main pole P1 described above, the play filling hole 35 thatpenetrates in a shape in which a hole shape is tapered from the outerside to the inner side in the radial direction is formed in anintermediate portion that is separated from the forming region of theriding protrusion 34 in the peripheral direction. As shown in FIG. 11,the play filling hole 35 described above is set such that the playfilling pin 21C protruding from the inner surface of the disc main body21 of the guide 20 is inserted into the play filling hole 35 when themain pole P described above is set on the guide 20. With such a setting,the play filling hole 35 does not block the movement of the main pole P1with the play filling pin 21C being positioned in a region where a holewidth on the outer side in the radial direction is wide when the mainpole P1 described above is in the unlocked state before meshing with theinner peripheral teeth 12A of the ratchet 10.

However, as shown in FIG. 10, as the main pole P1 described above ispushed outward in the radial direction and meshed with the innerperipheral teeth 12A of the ratchet 10, the play filling hole 35described above is configured such that the play filling pin 21C ispressed into a region having a narrow inner hole width in the radialdirection and can be switched to a state in which the play of the mainpole P1 in the peripheral direction is prevented. According to such aconfiguration, the main pole P1 is meshed with the inner peripheralteeth 12A of the ratchet 10 in a state where the play in the peripheraldirection is prevented, and the ratchet 10 and the guide 20 are lockedvia the main pole P1 in a state where the play in the peripheraldirection therebetween is prevented.

As shown in FIGS. 4 and 5 and FIGS. 19 and 20, each pole 30 describedabove is formed such that the offset surface portion 30B and the ridingprotrusion 34 are pushed out separately in the same axial direction in ahalf-blanking shape with respect to the main body surface portion 30A soas to be spaced from each other in the radial direction. At this time,the offset surface portion 30B of each pole 30 is formed such that aquality control surface Q for imparting accuracy to a molding surfaceobtained by the half blanking is set, not on an outer peripheral surfaceportion side which is pushed out in a half-blanking shape and whichfaces the outer side in the radial direction, but on an inner peripheralsurface portion (pressed surface portion 32) side of the main bodysurface portion 30A that is formed by the half blanking in a manner offacing the inner side in the radial direction. According to such aconfiguration, each pole 30 is configured such that the pressed surfaceportion 32 is accurately formed.

Further, the riding protrusion 34 of each pole 30 is formed such thatthe quality control surface Q for imparting accuracy to the moldingsurface obtained by the half blanking is set on the outer peripheralsurface portion 34A side that is pushed out in a half-blanking shape andthat faces the outer side in the radial direction. According to such aconfiguration, each pole 30 is configured such that the outer peripheralsurface portion 34A and the inclined surface 34B are accurately formed.As described above, each pole 30 is formed such that the offset surfaceportion 30B and the riding protrusion 34 are pushed out separately inthe half-blanking shape with respect to the main body surface portion30A so as to be spaced from each other in the radial direction, so thatthe quality control surfaces Q can be set on the front side and the backside to improve the accuracy of the molding surfaces.

Specifically, the pressed surface portion 32 of each pole 30 describedabove is configured such that each region separated from the formingpositions of the riding protrusions 34 on both sides in the peripheraldirection are pressed by corresponding pressing portions 44 of therotating cam 40 described with reference to FIG. 4 from the inner sidein the radial direction. Therefore, in reality, the pressed surfaceportion 32 of each pole 30 is configured such that the quality controlsurface Q is set in regions on both sides where the arrangement in theperipheral direction does not overlap with the riding protrusions 34,and the quality control surface Q is not set in a region where thearrangement in the peripheral direction overlaps with the ridingprotrusion 34. According to such a configuration, even if the offsetsurface portion 30B of each pole 30 and the riding protrusion 34 arearranged to overlap each other in the peripheral direction, the qualitycontrol surface Q can be appropriately set for each and molding can beperformed well.

(Rotating Cam 40)

As shown in FIG. 5, the rotating cam 40 is formed by one metal platemember being cut into a substantially disc shape and subjected to halfblanking in places in a plate thickness direction (the axial direction).The rotating cam 40 described above is set in a state of beingaccommodated in the cam accommodating groove 24B formed on the innersurface of the disc main body 21 of the guide 20 described above.

As shown in FIG. 9, the rotating cam 40 described above has a shapehaving substantially the same plate thickness as each pole 30 describedabove, and is arranged to be surrounded by the main body surface portion30A of each pole 30 from the outer peripheral side in a manner of beingsandwiched between the inner surface of the disc main body 21 of theguide 20 described above and the offset surface portion 30B of each pole30 pushed out in a half-blanking shape in the axial direction.

As shown in FIG. 5, at the central portion (on the central axis C) ofthe rotating cam 40 described above, a through hole 41 is formed inwhich the operation pin 5A integrally connected to the reclining lever 5described above with reference to FIG. 1 is inserted from the inner sidein the axial direction and is integrally mounted in a rotationaldirection. The operation pin 5A described above is inserted through thethrough hole 41 of the rotating cam 40 described above from the innerside to the outer side in the axial direction, and is connectedintegrally with the reclining lever 5 described above with reference toFIG. 1 at that point. According to such a configuration, the operationpin 5A is operated to integrally rotate with the rotating cam 40 inaccordance with the operation of pulling up the reclining lever 5described above.

The operation pin 5A described above is integrally connected to theoperation pin 5A inserted into the device 4 on the other side describedabove with reference to FIG. 1 via a connecting rod 5B. According tosuch a configuration, the operation pin 5A on the other side is alsointegrally rotated, and the rotating cam 40 of the device 4 on the sameside is also integrally rotated by the operation of pulling up thereclining lever 5 described above.

As shown in FIG. 5, the rotating cam 40 described above is formed in asubstantially disc shape that is slightly larger than the through hole21A formed at the central portion (on the central axis C) of the guide20 described above, and two hooking pins 43 are formed so as to protrudein the axial direction on an outer surface of the rotating cam 40 facingthe inside of the through hole 21A of the guide 20. As shown in FIGS. 2and 6, an inner end portion 51 of the lock spring 50 to be describedlater is hooked on each of the hooking pins 43 described above in amanner of being sandwiched therebetween, so as to be integrally fixed.Further, on an inner surface of the rotating cam 40 described abovefacing the offset surface portion 30B of each pole 30, three pull-inpins 42 which are set to be respectively inserted into correspondingpull-in holes 33 formed in each pole 30 are formed to protrude in theaxial direction.

The rotating cam 40 described above is assembled to the guide 20described above in a state of being elastically supported via the lockspring 50. That is, from the state of being set in the cam accommodatinggroove 24B of the guide 20 described above, the rotating cam 40 isassembled to the guide 20 in a state of being elastically supported viathe lock spring 50 by setting the lock spring 50 in the through hole 21Aof the guide 20, in a manner that the inner end portion 51 of the lockspring 50 is hooked between the hooking pins 43 projecting from theouter surface of the rotating cam 40 facing the inside of the throughhole 21A of the guide 20, and the outer end portion 52 of the lockspring 50 is hung in the hanging hole 21Aa extending from the throughhole 21A of the guide 20.

According to such an assembling, as shown in FIG. 9, the rotating cam 40is supported in a state of being sandwiched in the axial directionbetween the disc main body 21 of the guide 20 described above and theoffset surface portion 30B of each pole 30 pushed out in a half-blankingshape in the axial direction, and in the radial direction, is providedto be surrounded from the outer side in the radial direction by thepressed surface portion 32, which is an inner peripheral surface portionof the main body surface portion 30A of each pole 30.

The rotating cam 40 described above is always in a state of beingrotationally biased in the counterclockwise direction shown in FIG. 10with respect to the guide 20 by the spring biasing force of the lockspring 50 (see FIGS. 2 and 6) hooked between the rotating cam 40 and theguide 20. Due to the rotation in the counterclockwise direction by thebiasing, the rotating cam 40 is operated by each pressing portion 44formed to protrude at a plurality of positions in the peripheraldirection on the outer peripheral surface portion of the rotating cam40, so as to push the pressed surface portion 32 of each pole 30 fromthe inner side to the outer side in the radial direction.

Further, by the operation of pulling up the reclining lever 5 describedabove with reference to FIG. 1, the rotating cam 40 described above isrotated through the operation pin 5A in the clockwise direction shown inthe figure, which is a direction opposite to the biasing directiondescribed above as shown in FIG. 11. As a result, the rotating cam 40 isoperated to pull each pole 30 inward in the radial direction by theshape in which each pull-in pin 42 inserted into the pull-in hole 33 ofeach pole 30 moves radially outward of each pull-in hole 33 while movingin the peripheral direction in each pull-in hole 33.

Specifically, the rotating cam 40 described above is configured suchthat, in a state where each pole 30 is pushed out from the inner side inthe radial direction by a rotational force by the spring biasing forceof the lock spring 50 and meshed with the inner peripheral teeth 12A ofthe ratchet 10 (locked state) as shown in FIG. 10, the inner end portion51 of the lock spring 50 hooked on the hooking pin 43 is positioned in aregion in the peripheral direction between two guide walls M1 on anupper left side and an upper right side in the figure among the threeguide walls 23 formed on the guide 20.

In the above state, the rotating cam 40 receives an action of a biasingforce that is eccentric toward the outer side in the radial direction inaddition to a rotational biasing force in the counterclockwise directionin the figure by the spring biasing force received from the inner endportion 51 of the lock spring 50. Even so, when the poles 30 mesh withthe inner peripheral teeth 12A of the ratchet 10, the rotating cam 40 issupported by the poles 30 and held in the central portion (on thecentral axis C) of the guide 20 in a centered state.

However, in a state where the rotating cam 40 described above is rotatedin the clockwise direction shown in the figure against the springbiasing force of the lock spring 50 described above, and each pole 30does not mesh with the inner peripheral teeth 12A of the ratchet 10 asshown in FIG. 11, due to a biasing action in an eccentric directionreceived from the inner end portion 51 of the lock spring 50 describedabove, the rotating cam 40 is rotated in the clockwise direction shownin the figure in a manner of sliding on the support surfaces 23B on aninner peripheral side of two guide walls M1 while being pressed againstthe support surfaces 23B of these two guide walls M1 as shown in FIG.16. At this time, unlike the other two guide walls M1, one remainingguide wall M2 is formed in such a manner that a slight gap T in theradial direction is set between the outer peripheral surface of therotating cam 40 described above and the guide wall M2.

According to such a configuration, as shown in FIG. 16, in the two guidewalls M1 against which the rotating cam 40 is pressed by the biasingaction of the lock spring 50, while the rotating cam 40 is properlysupported so as not to move in an axial displacement direction(eccentric direction), the rotating cam 40 properly escapes the movementwhen a shape is rattled in a certain direction of the one remainingguide wall M2 with these two guide walls M1 as a fulcrum, so that therotating cam 40 can be smoothly slid and rotated in a releasingdirection without eccentricity.

(Outer Peripheral Ring 60)

As shown in FIGS. 4 and 5, the outer peripheral ring 60 is formed into asubstantially cylindrical shape with a hollow disc-shaped seat bypunching one thin plate material into a ring shape, and drawing an outerperipheral portion of the punched hollow disc into a cylindrical shapeprotruding in the plate thickness direction (axial direction). As aresult, the outer peripheral ring 60 has a hollow disc-shaped flangeportion 62 that faces a surface in the axial direction, and a couplingportion 61 that protrudes in a substantially cylindrical shape in theaxial direction along an outer peripheral edge portion of the flangeportion 62.

Specifically, the outer peripheral ring 60 described above is formed bypushing out the coupling portion 61 described above from an outerperipheral portion of the flange portion 62 in a shape protruding in twosteps in the axial direction, so as to be formed in a steppedcylindrical shape having an inner and outer two-step cylindrical shapein which a stepped portion 63 that is smaller in the axial directionthan the coupling portion 61 and protrudes in a substantiallycylindrical shape is formed on an inner peripheral side of the couplingportion 61. After the three poles 30, the rotating cam 40, and the lockspring 50 are set on the guide 20 described above and the guide 20 andthe ratchet 10 are assembled, the assembled unit is set inside thecylindrical inner portion and the coupling portion 61 is welded to theguide 20, so that the outer peripheral ring 60 described above ismounted over outer peripheral portions of the ratchet 10 and the guide20.

Specifically, the unit described above is set to be assembled inside thecylindrical inner portion from the ratchet 10 first, so that as shown inFIGS. 9 and 15, the outer peripheral ring 60 described above is set insuch a manner that an end portion on the inner side in the radialdirection of the flange portion 62 is abutted against an inclinedsurface 13G that is obliquely directed outward in the radial directionand formed on the outer side surface portion in the axial direction ofthe intermediate cylindrical portion 13 of the ratchet 10 oversubstantially the entire peripheral direction. With such a setting, thecylindrical portion 22 of the guide 20 is set in the cylindricalcoupling portion 61 of the outer peripheral ring 60 so as to be fittedtherein.

Therefore, after the above setting, the coupling portion 61 of the outerperipheral ring 60 is coupled to the cylindrical portion 22 of the guide20 fitted therein by laser welding from the outer peripheral side, sothat the outer peripheral ring 60 is mounted over the outer peripheralportions of the ratchet 10 and the guide 20. The inclined surface 13Gformed on the outer side surface portion of the intermediate cylindricalportion 13 of the ratchet 10 described above is formed over the entirearea of the ratchet 10 in the peripheral direction so as to draw aprefixed cone shape around the central portion (on the central axis C)of the ratchet 10.

According to such an assembling, the outer peripheral ring 60 isintegrally coupled to the guide 20 described above, so that the ratchet10 is held with respect to the guide 20 with the play being filled inthe axial direction and the radial direction by the flange portion 62.Specifically, the outer peripheral ring 60 described above is set in astate where the flange portion 62 thereof is abutted against theinclined surface 13G of the ratchet 10 in the axial direction, and thecoupling portion 61 is welded and assembled to the cylindrical portion22 of the guide 20 that is assembled to the ratchet 10 and positioned inthe axial direction. As a result, the outer peripheral ring 60 is in astate in which the ratchet 10 is loosened in the axial direction betweenthe flange portion 62 and the disc main body 21 of the guide 20, and theratchet 10 is supported with respect to the guide 20 such that theratchet 10 can be smoothly rotationally moved when unlocked withoutrattling in the axial direction and the radial direction.

(Summary)

As described above, according to the device 4, in the coupling region A4(fourth region) coupled with the seat frame 2F of the outer side surfaceportion of the ratchet 10, a portion corresponding to the other regionA3 (third region) of the protruding portion 13 has the expansion surfaceportion 11B that is wider outward in the radial direction than a portioncorresponding to the free region A2 (second region). Therefore, thedevice 4 can expand the portion where the ratchet 10 is coupled to theseat frame 2F to the outer side in the radial direction as compared witha seat reclining device in related art.

Furthermore, according to the device 4, a wide space in which a spacearound both ends of the dowels 14 (projections) in the peripheraldirection and a space on the outer side in the radial direction of thedowels 14 are continuous can be assigned in the coupling region A4(fourth region). Therefore, it is possible to assign a wider area wherethe ratchet 10 is coupled to the seat frame 2F.

(Other Embodiments)

Modes for carrying out the present invention has been described with oneembodiment, but the present invention can be carried out in variousmodes other than the above embodiment. For example, the vehicle seatreclining device of the present invention can be applied to not only aseat other than a right seat of an automobile, but also to a seats forvehicles other than automobiles such as trains, and seats provided forvarious vehicles such as aircraft and ships. Further, the vehicle seatreclining device described above is configured such that a seat back isconnected to a seat cushion in a state where a backrest angle can beadjusted, and may also be configured such that the seat back isconnected to a base such as a bracket fixed to the vehicle body side ina state where the backrest angle can be adjusted.

Further, the vehicle seat reclining device may be configured such thatthe ratchet is coupled to a member such as a seat cushion that is fixedto the vehicle body side, and the guide is coupled to the seat back.Further, the plurality of poles forming the lock mechanism of thevehicle seat reclining device may be provided by arranging two or fouror more in the peripheral direction. The arrangement of each pole in theperipheral direction is not limited to being evenly arranged, but may bearranged to be offset.

Further, the cam that operates to push each pole outward in the radialdirection may be of a type that pushes each pole outward in the radialdirection by rotation, or may be of a type that slides each pole in theradial direction so as to push out each pole in a radial directionintersecting the sliding direction (see JP-A-2015-227071). The operationof pulling back each pole inward in the radial direction may beperformed by a member separate from the cam, such as a release plate(see the same publication).

Further, the coupling region which is abutted against and coupled to theseat frame of the ratchet may be abutted against and coupled to the seatframe without the dowel.

Here, characteristics of the embodiment of the vehicle seat recliningdevice 4 according to the present invention described above will bebriefly summarized in the following [1] and [2].

[1]

A vehicle seat reclining device (4) including:

a disc-shaped ratchet (10) and a disc-shaped guide (20), the ratchet(10) and the guide (20) being coaxially assembled in a relativelyrotatable manner;

a lock mechanism provided between the ratchet (10) and the guide (20),and capable of restricting relative rotation between the ratchet (10)and the guide (20); and

a retaining ring (60) retaining an assembled state of the ratchet (10)and the guide (20),

in which the lock mechanism includes: a plurality of poles (30)supported by the guide (20) movably in a radial direction, the pluralityof poles (30) meshing with the ratchet (10) when moving outward in theradial direction so as to restrict the relative rotation between theratchet (10) and the guide (20); and a cam (40) for moving the pluralityof poles (30) outward or inward in the radial direction,

in which the ratchet (10) has: an annular protruding portion (13) wherean outer peripheral portion of the ratchet (10) protrudes to one side inan axial direction; and an outer side surface portion configured to facea seat frame (2F) on the other side in the axial direction of theratchet (10),

in which the protruding portion (13) has: a first region (A1) in which aspecific pole (30) of the plurality of poles (30) is allowed to moveoutward in the radial direction and to mesh with the ratchet (10); asecond region (A2) in which the specific pole (30) is prevented frommoving outward in the radial direction and from meshing with the ratchet(10); and a third region (A3) in which another pole (30) is located whenthe specific pole (30) is in the second region (A2), the first region(A1), the second region (A2), and the third region (A3) being arrangedin a peripheral direction,

in which the outer side surface portion has a fourth region (A4)configured to be in contact and coupled with the seat frame (2F), and

in which the protruding portion (13) has a shape in which the thirdregion (A3) extends further outward in the radial direction than thesecond region (A2), so that the fourth region (A4) has a shape in whicha portion of the fourth region (A4) which corresponds to the thirdregion (A3) is wider outward in the radial direction than a portion ofthe fourth region (A4) which corresponds to the second region (A2).

[2]

The vehicle seat reclining device (4) according to [1],

in which the outer side surface portion has a projection (14) protrudingtoward the other side in the axial direction so as to be fitted into theseat frame (2F), the projection (14) being provided on the fourth region(A4), and

in which the projection (14) has a shape in which a length of theprojection (14) in the peripheral direction is equal to or less than alength of the third region (A3) in the peripheral direction.

This application is based on Japanese Patent Application No. 2018-031927filed on Feb. 26, 2018, the contents of which are incorporated herein byreference.

INDUSTRIAL APPLICABILITY

According to the vehicle seat reclining device of the present invention,it is possible to expand a coupling region of a ratchet to a seat frame.The present invention having this effect is useful for a seat of anautomobile or the like, for example.

REFERENCE SIGNS LIST

-   -   1 seat    -   2 seat back    -   2F side frame (seat frame)    -   2Fa fitting hole    -   2Fb passage hole    -   3 seat cushion    -   3F reclining plate    -   3Fa fitting hole    -   3Fb passage hole    -   4 seat reclining device (vehicle seat reclining device)    -   5 reclining lever    -   5A operation pin    -   5B connecting rod    -   6 return spring    -   10 ratchet    -   11 disc main body    -   11A through hole    -   11B expansion surface portion    -   12 cylindrical portion    -   12A inner peripheral teeth    -   13 intermediate cylindrical portion (protruding portion)    -   13A region    -   13B region    -   13C region    -   13D first projection    -   13E second projection    -   13F escape recess    -   13G inclined surface    -   A1 lock region (first region)    -   A2 free region (second region)    -   A3 other region (third region)    -   A4 coupling region (fourth region)    -   14 dowel    -   W welding portion    -   20 guide    -   21 disc main body    -   21A through hole    -   21Aa hanging hole    -   21B dowel    -   21C play filling pin    -   22 cylindrical portion    -   23 guide wall    -   23A restriction surface    -   23B support surface    -   23C bead portion    -   M1 guide wall    -   M2 guide wall    -   T gap    -   24A pole accommodating groove    -   24B cam accommodating groove    -   30 pole    -   30A main body surface portion    -   30B offset surface portion    -   31 outer peripheral teeth    -   32 pressed surface portion    -   33 pull-in hole    -   34 riding protrusion    -   34A outer peripheral surface portion    -   34B inclined surface    -   35 play filling hole    -   P1 main pole (specific pole)    -   P2 sub pole (another pole)    -   Q quality control surface    -   40 rotating cam (cam)    -   41 through hole    -   42 pull-in pin    -   43 hooking pin    -   44 pressing portion    -   50 lock spring    -   51 inner end portion    -   52 outer end portion    -   60 outer peripheral ring (retaining ring)    -   61 coupling portion    -   62 flange portion    -   63 stepped portion    -   C central axis

The invention claimed is:
 1. A vehicle seat reclining device comprising:a disc-shaped ratchet and a disc-shaped guide, the ratchet and the guidebeing coaxially assembled in a relatively rotatable manner; a lockmechanism provided between the ratchet and the guide, and capable ofrestricting relative rotation between the ratchet and the guide; and aretaining ring retaining an assembled state of the ratchet and theguide, wherein the lock mechanism includes: a plurality of polessupported by the guide movably in a radial direction, the plurality ofpoles meshing with the ratchet when moving outward in the radialdirection so as to restrict the relative rotation between the ratchetand the guide; and a cam for moving the plurality of poles outward orinward in the radial direction, wherein the ratchet has: an annularprotruding portion where an outer peripheral portion of the ratchetprotrudes to one side in an axial direction; and an outer side surfaceportion configured to face a seat frame on the other side in the axialdirection of the ratchet, wherein the protruding portion has: a firstregion in which a specific pole of the plurality of poles is allowed tomove outward in the radial direction and to mesh with the ratchet; asecond region in which the specific pole is prevented from movingoutward in the radial direction and from meshing with the ratchet; and athird region in which another pole is located when the specific pole isin the second region, the first region, the second region, and the thirdregion being arranged in a peripheral direction, wherein the outer sidesurface portion has a fourth region configured to be in contact andcoupled with the seat frame, and wherein the protruding portion has ashape in which the third region extends further outward in the radialdirection than the second region, so that the fourth region has a shapein which a portion of the fourth region which corresponds to the thirdregion is wider outward in the radial direction than a portion of thefourth region which corresponds to the second region.
 2. The vehicleseat reclining device according to claim 1, wherein the outer sidesurface portion has a projection protruding toward the other side in theaxial direction so as to be fitted into the seat frame, the projectionbeing provided on the fourth region, and wherein the projection has ashape in which a length of the projection in the peripheral direction isequal to or less than a length of the third region in the peripheraldirection.